[Engineering Version] Daily Question 20180621
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The surface layer of the drainage surface should be made of ( ) material, while the base layer should be made of ( ). A. Concrete, concrete B. Mortar, concrete C. Concrete, mortar D. Crushed bricks, concrete E. Fine sand, mortar. Answer: AB 【Explanation】The surface layer of the apron should be made of water-impermeable materials such as concrete or mortar, while the base layer should be constructed using concrete or concrete with crushed bricks.
A. Concrete, concrete B. Mortar, concrete
Concrete, concrete； Mortar, concrete